Usually niche food of acquired taste & often questionable origin enjoyed by only a small amount of people. It can also be a tasty food with a sky-high price tag.

While Wikipedia quotes it as being "a food item that is considered highly desirable in certain cultures," what they really mean is that it's panned by most of the population, but more people in that country will eat it than anywhere else.

A delicacy can range from poor people food (like the natto parents will force their children to eat), to tiny portions of overhyped rich people food (like french truffles).

Other delicacies are used purely for novelty & entertainment value outside their country of origin, such as eating a can of Surströmming, Balut, Pidon, or drinking Birds Nest Soup for a web review series about gross foods.

Aileen sent me a can of Haggis; a delicacy of Scotland. I was reluctant to eat it because it contained offal & because canned versions are never better than fresh. She reminded me what goes into sausages. I tried it & was relieved that it tasted like corned beef hash.